1. Field of the Invention
The present invention relates to keyboard musical instruments such as electronic organs, and more particularly to improvements in or to the cover opening/closing mechanism of keyboard musical instruments.
2. Prior Art
Conventionally, as a cover for use in keyboard musical instruments, such as electronic organs, there is known a so-called sliding manual cover, which is disposed for sliding motion on a pair of left and right manual cover guides in forward and rearward directions with respect to the main body of a keyboard musical instrument. Further, a cover opening/closing mechanism for keyboard musical instruments having the above-mentioned sliding manual cover is also known from Japanese Utility Model Publication No. 7-49511, which includes a pair of pinions arranged at left and right sides of a rear end of the sliding manual cover (an end thereof in a direction in which the cover is opened), and a pair of racks provided, respectively, on a pair of left and right manual cover guides, and the pinions engage the racks and move along the latter as the sliding manual cover is opened or closed, to thereby permit smooth opening/closing motions of the sliding manual cover.
According to the known cover opening/closing mechanism for keyboard musical instruments, however, it is essentially required to provide in a rear portion of the main body of the keyboard musical instrument a space for accommodation of the sliding manual cover in an open position, which results in an increased axial size of the main body and hence an overall size of the same, leading to an increased cost of the component materials as well as restrictions on the design of the musical instrument. That is, the axial size of the sliding manual cover is determined by the size of the keyboard, the sizes of panels of the musical instrument, etc. and therefore a limitation is imposed upon reducing the size of the sliding manual cover, while on the other hand, when the sliding manual cover is open, the keyboard has to be entirely exposed to the outside, thus automatically determining the minimum required axial size of the space for accommodation of the sliding manual cover.
On the other hand, there is also known from Japanese Utility Model Publication No. 59-16944 a cover opening/closing mechanism for keyboard musical instruments, which is applied to a shutter-like sliding manual cover formed of a plurality of cover components pivotally coupled together to permit the cover to be flexed and has an accommodation space for the sliding manual cover, which is arranged such that as the sliding manual cover is opened, a rear end thereof is downwardly guided on a curved path along a back panel of the musical instrument. According to this known mechanism, the accommodation space for the sliding manual cover downwardly extends such that the axial size of the main body of the keyboard musical instrument can be reduced.
According to the known mechanism, however, since the sliding manual cover is caused to be downwardly suspended, the weight of the sliding manual cover acts upon manual cover slides and a curved portion of the accommodation space, which makes it impossible to smoothly open or close the sliding manual cover. During the closing operation in particular, the user feels the pressure of the sliding manual cover on his hands, while during the opening operation, he feels that his hands are pulled by the sliding manual cover immediately before completion of the opening motion of the cover. These inconveniences cannot be eliminated even if pinions and racks are employed, which engage each other and the pinions move along the racks as the sliding manual cover is opened and closed, still leaving a feeling of unsmoothness due to the weight of the sliding manual cover. This feeling of unsmoothness is particularly strong during the closing operation of the sliding manual cover.
Thus, the conventional cover opening/closing mechanisms have the disadvantage that it is difficult to satisfy the requirements of both reduction of the size of the accommodation space for the sliding manual cover and smooth opening/closing operation of the sliding manual cover, without making the construction complicate.